• Title, Summary, Keyword: 횡방향 가속도

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Evaluation of Horizontal Curve Transition Section Using Lateral Acceleration Model (횡방향 가속도 모영을 이용한 곡선부 도로의 변이구간 평가에 관한 연구)

  • Park, Je-Jin;Kim, Yong-Gil;Ko, Yeong-Sun;Ha, Tae-Jun
    • International Journal of Highway Engineering
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    • v.10 no.2
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    • pp.135-143
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    • 2008
  • According to the present highway design criteria, there are minimum standards which re ade from special design speeds. If some highways are satisfied the standards, it regards he highway as safety. In reality, however, most drivers drive a car at different speed compared with design speed. It is very dangerous for drivers especially at transition sections between curve and horizontal curve sections. Hence, this study calculated the rate of changing and horizontal acceleration at each section. Moreover, this study evaluated thesafety of design at curve transition sections and then calculated lateral acceleration and curve radii. This study found the minimum standards which are using as basic safety standards are not appropriate for measuring driver's safety.

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Dynamic Characteristics of Railway Plate Girder Bridges with Increase of Diesel Locomotive Speed (철도차량의 증속에 따른 판형교의 진동특성)

  • Cho, Eun Sang;Kim, Hyun Min;Hwang, Won Sup;Oh, Ji Taek
    • Journal of Korean Society of Steel Construction
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    • v.18 no.6
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    • pp.769-782
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    • 2006
  • As the ambient vibration test (AVT) of railway bridges has a limited range of speed, it has a limitation in examining the dynamic behavior of bridges accordingto speed. Thus, in order to analyze the correlation between the speed of a train passing over a bridge and the bridge's dynamic response, we conducted a speed-increasing experiment using a real diesel locomotive. To analyze the acceleration response characteristics, we attached seven vertical accelerometers at equal intervals throughout the entire section of the bridge except the supports, and one horizontal accelerometer to the middle span. Linear variable differential transformers (LVDT) were installed at the bridge's center in both vertical and horizontal directions to investigate the vertical and horizontal behaviors. The test train was statically loaded at the center and at the end of the bridge. And its speed was increased from 5 km/h to 90 km/h. With data obtained from the experiment, the vibration level was evaluated in each direction by the filtering frequency, and the level of horizontal vibration was examined in comparison with vertical vibration. The displacement and wheel load variation was analyzed by speed.

Analysis of Comfort on Transition Curve based on the Measured Data (실측데이터에 의한 완화곡선 승차감 평가)

  • Choi, Il-Yoon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.5
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    • pp.3573-3578
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    • 2015
  • Transition curves are located between curve and straight section in railway. These transition curves are vulnerable to the ride comfort of passengers and safety of a vehicle because lateral acceleration, lateral jerk and roll velocity increase as curvature and cant change along the transition curves. In this paper, ride comfort on the transition curve was calculated on the basis of lateral acceleration and roll velocity measurements. The evaluation of ride comfort was conducted according to the methodology specified in European Standard. The distribution characteristics of the comfort index were investigated for the korean conventional line from the evaluation results. The influence of the curve radius and the vehicle speed on the ride comfort index was also investigated. Finally, the relationship between ride comfort and the rate of cant changes on transition curves was analyzed.

소격격자 재균형법을 이용한 노달 해석함수 전개해의 가속화 기법

  • 조병오;노재만;이창호;지성균
    • Proceedings of the Korean Nuclear Society Conference
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    • pp.25-31
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    • 1997
  • 현대적 노달방법은 다차원 중성자 확산방정식을 풀기 쉽고 계산시간을 단축시킬 수 있도록 각 방향에 대하여 횡방향으로 적분하여 등가인 차원 수 만큼의 1차원 중성자 확산 방정식을 만들어 풀고 있다 이 과정에서 횡방향 누출 중성자 적분항을 적절히 근사해야함이 필수적인데 이로 인하여 계산의 정확도를 손상하게 될 수가 있다. 이러한 횡방향 누출 중성자 근사를 제거하여 계산의 정확도를 향상시킨 것이 노달 해석함수 전개법(Analytic Function Expansion Nodal Method)이다. 그러나 이 방법은 기존의 노달 방법 보다는 계산시간이 다소 많이 소요되는 단점이 있었다. 본 논문에서는 소격격자 재균형 가속법(Coarse-Mesh Rebalance Acceleration Method)을 노달 해석함수 전개법에 적용하면 계산의 정확도는 그대로 유지되면서도 속도는 크게 향상시킬 수 있음을 보여 준다.

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Development of Piezoelectric Accelerometers and Their Performance Evaluation (압전형 가속도 센서의 개발과 특성평가에 관한 연구)

  • 이두희;임병덕;이용봉;김정태
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.16 no.4
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    • pp.811-818
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    • 1992
  • The sensor technology has becoming emerging area as the automation process in industry requires higher productivity, better quality, and the reliability. In this research, the dynamic measuring sensor such as piezoelectric accelerometers has been developed. Especially, the research concentrates on a design methodology, an analysis of the structural characteristics, and a method of the performance evaluation. The fabricated piezoelectric accelerometers show that the performance characteristics is better than commercial products available in the current market.

A Study on the Laterally Dynamic Characteristics and the Finite Elements of Concrete Slab Track (슬래브궤도에 대한 유한요소와 횡방향 동특성에 관한 연구)

  • 조병완;권병윤;태기호;마성운
    • Proceedings of the KSR Conference
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    • pp.500-507
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    • 2001
  • In this study, Interaction among each element was construed by the unit of new stiffness matrix to analyze the finite element about Japanese precast concrete slab track and improved slab track. Dynamic analysis which is assumed a static analysis and a trainload on the transverse and the longitudinal load of the train into a series periodic function was performed by using the common program. And then, the difference of the movement between an improved section and an existing structure type was realized. Longitudinal static analysis indicated that the stress of the improved section is smaller than that of the protrusion of the existing slab track. And static and dynamic analysis on transverse load showed a little decrease of the displacement on new slab track. But the dynamic analysis result showed that new track system was considerably decreased by 30% compared with the existing Japanese slab track.

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Driving Behavior Analysis of Commercial Vehicles(Buses) Using a Risky Driving Judgment Device (위험운전판단장치를 이용한 사업용자동차(버스)의 운전행태분석)

  • Oh, Ju-Taek
    • International Journal of Highway Engineering
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    • v.14 no.1
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    • pp.103-109
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    • 2012
  • Digital speedometer which is supposed to provide the basic data for analyzing human factors of drivers has a limitation for human behavior studies of drivers, because it records limited driving information including GPS velocities. Besides, Black Box, which is currently being actively commercialized in the market, records mostly vehicles' risky patterns rather than drivers' behaviors. As a result, it also shows a limit to analyze dangerous driving patterns. This study performed a risky driving study for human factor analysis. This study conducted before and after comparisons for real time warning study using a risky driving judgment device. The analysis was conducted based on Longitudinal acceleration, Lateral acceleration, and Yaw rate of vehicles.

Dynamic Response and Reinforcement of the Railway Plate Girder Bridges (무도상 철도판형교의 동적응답특성 및 보강방안)

  • Hwang, Won Sup;Cho, Eun Sang;Oh, Ji Taek;Kim, Hyun Min
    • Journal of Korean Society of Steel Construction
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    • v.19 no.3
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    • pp.281-290
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    • 2007
  • In this paper, the dynamic behavior of a 12m plate girder railway bridge is analyzed using the commercial FEM program. A time history load is applied to a standard train load via the shape function ofthe beam element. In addition, lateral behavior characteristics were simulated using the Klingel sine movement. A feasibility study of the FEM program and an analysis were performed by comparing the displacement and the acceleration, from the experimental data and the results of the FEM analysis. the time history of the lateral and vertical displacements are reflected in the experimental results. Six kinds of reinforcements were studied from the effects of the displacement and the acceleration. The RF-1 model that was applied to the upper lateral bracing system, and the RF-3 model that reinforced the plate, turned out to be the most effective reinforcement methods with respect to weight limits and construction simplification.

Development and Evaluation of ESP Systems for Enhancement of Vehicle Stability during Cornering (II) (차량의 선회시 주행 안정성 강화를 위한 ESP 시스템 개발 및 성능 평가 (II))

  • Song, Jeong-Hoon
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.30 no.12
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    • pp.1551-1556
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    • 2006
  • Two yaw motion control systems that improve a vehicle lateral stability are proposed in this study: a rear wheel steering yaw motion controller (SESP) and an enhanced rear wheel steering yaw motion controller (ESESP). A SESP controls the rear wheels, while an ESESP steers the rear wheels and front outer wheel to allow the yaw rate to track the reference yaw rate. A 15 degree-of-freedom vehicle model, simplified steering system model, and driver model are used to evaluate the proposed SESP and ESESP. A robust anti-lock braking system (ABS) controller is also designed and developed. The performance of the SESP and ESESP are evaluated under various road conditions and driving inputs. They reduce the slip angle when braking and steering inputs are applied simultaneously, thereby increasing the controllability and stability of the vehicle on slippery roads.

Study on Lateral Flow Distribution and Momentum Analysis at Flood season and Neap tide of the Seokmo Channel in the Han River estuary (소조기 홍수시 한강하구 석모수로에서의 횡 방향 2차 흐름 및 운동량 분석)

  • Choi, Nak Yong;Woo, Seung-Buhm
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.24 no.6
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    • pp.390-399
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    • 2012
  • This research observed the cross section current of 7 survey lines in Seokmo Channel of Gyeonggi bay with a lot of freshwater inflow and S-shaped for 13 hours during flood season and neap tide. We indicated the distribution of the current velocity by comprehending the speed and direction of the current velocity of each line during maximum flood, ebb tide and observed the distribution of salinity. Moreover, in order to understand what lateral momentum causes the lateral flow in each survey line, we practiced the momentum analysis through the observation data. As a result, the lateral baroclinic pressure gradient force and vertical friction of the Seokmo channel during neap tide were the strongest, and this is why the flow by the distribution of salinity and stratification most often occurs. In north of the Seokmo channel, where have wide intertidal and a lot of freshwater inflow, the secondary circulation is caused by balance of lateral baroclinic pressure gradient force and other forces, and the vertical friction was strong in the lines with small depth. On the other hand, in the southern part of the Seokmo channel where the water is deep and the waterway is curved, the advective acceleration and centrifugal force become stronger by the geographical causes during ebb and the influence of fresh water. Therefore, the lateral flow in the Seokmo channel was caused by the distribution of the momentum that differs by location, depth, curve, etc.